Ned Lamont, the political upstart who challenged U.S. Sen. Joe Lieberman four years ago, plans to officially announce his bid for Connecticut governor next week, according to a state Democratic official.

The official told The Associated Press on Friday that Lamont will declare his candidacy Tuesday at the Old State House in downtown Hartford, the same location where Lamont announced his Senate run back in March of 2006. The official spoke on condition of anonymity because the campaign has not yet made the announcement.

Lamont won the 2006 Democratic primary against Lieberman, but the senator ran in the general election as an independent and won. Lamont spent $16 million of his own money and was able to tap into the discontent among many Democrats over Lieberman's support of the war in Iraq.

The 56-year-old Greenwich businessman, founder of a cable television company that services colleges and universities, formed an exploratory committee in November for the governor's race and has said he's willing to spend his own money even though Connecticut has a public financing system.

Lamont's campaign would not confirm Tuesday's announcement, which was first reported by the Connecticut Post on its Web site.

Douglas Schwartz, director of the Quinnipiac University Poll, said Lamont is the best known candidate in the race, which appears to be wide open since Republican Gov. M. Jodi Rell announced she is not running for re-election.

"He got national attention when he ran against Lieberman in 2006 so he starts off with an immediate edge in name recognition," Schwartz said.

"And he starts out with a big edge in money," Schwartz added. "In the primary, it is especially important because he's going to be able to define his opponents before they are able to define themselves."

Former state House Speaker James Amann exited the governor's race on Thursday, meaning Lamont would be the only declared candidate for the Democratic nomination. Four other Democratic candidates — former Stamford Mayor Dannel Malloy, Simsbury First Selectwoman Mary Glassman, Ridgefield First Selectman Rudy Marconi and health care advocate Juan Figueroa — still have exploratory committees, but haven't committed to running.

A Quinnipiac Poll from January showed that 27 percent of registered Democrats would back Lamont in a primary. Schwartz said Malloy is within striking range and it's still possible for a lesser known candidate to emerge from the pack of Democrats.

On the Republican side, another wealthy Greenwich businessman, Tom Foley, has announced a run.

Lamont has said that he's still complying with the rules of Connecticut's public financing program, such as refusing contributions from lobbyists and state contractors, even though he hasn't yet decided whether to participate. Last month, Lamont said he's concerned about agreeing to the spending limits if Foley pours millions of dollars of his own money into the race.

"I'm a strong believer in arms control, but I don't believe in unilateral disarmament," Lamont said. "If everybody's playing by the same rules, its an easier decision. Right now, somebody's already out of the box and that impacts my thinking."

Besides Foley, there are seven other Republicans who've formed candidate or exploratory committees in the race.